The both ends of the girder of the guideway must be respectively equipped with a bearing. All the girders of the guideway have to be aligned and adjusted in assembling and maintenance. The alignment and the adjustment may be carried out by adjusting the bearing; usually the position adjustment of the bearing is operated by inserting some steel flat liners and a steel wedge into between the adjusting holes on the lower hem of bearing and anti-shear tenon of bearing bottom plate. But inconvenience in operation, requiring a lot of work and high cost, and jamming of the steel wedge liner are the disadvantages of the aforesaid method. Moreover, the adjusting wedge can not be retreated when there is an inaccurate or incorrect adjustment.
When the modern high-speed track-bound system is used for the high-speed running of maglev train, the system has an extremely high accuracy requirement on the structure of track. It is demanded that the deformation and the deflection caused by temperature difference and dynamic load of track must be controlled within a very small range. In high speed running of the modern high speed maglev train, etc., the loads, inclusive of the self-weight of the superstructure of the guideway, are all transferred to the substructure of the guideway through bearing. In the meantime, as to the bearing itself as a part of the guideway, its deformation or displacement due to the action of external forces and temperature is superposed and accumulated on the guideway and it will produce a disadvantageous effect on the high speed running of the track-borne transportation. These small deformation or displacement will not cause any problems on the traditional bridge structure and etc, but as for the guideway used for the running of the track borne vehicle of the modern high speed transportation, especially for the guideway of the maglev train, these small deformation will negatively affect the high speed running of the train. Meanwhile, as time goes on, the foundation settlement will unavoidably occur due to the action of the gravity force applied on the substructure of the guideway, especially under the condition of the soft soil ground, this settlement will become relatively big; and the settlement of the lower structure, especially the unequal settlement between two adjacent columns, will cause the guideway superstructure to be displaced or sidewise dislocated. As for the high speed track borne transportation system, such as maglev train, the aforesaid displacement or sidewise dislocation can not be admitted absolutely. When the train runs after a time, if the magnitudes of the deformation and the deflection of the guideway caused by the settlement are very large and exceed the maximum allowable values, usually a correction of the guideway must be done by adjusting bearing. Namely, the track borne transportation, especially the modern high speed maglev train and etc. puts forward a quite higher requirement on the bearing of the guideway girder.